Method and means for pressure filtering

ABSTRACT

Method and apparatus for pressure filtering in a pressure filter (1) comprising a frame carrying press plates (3-6), which can be brought together and apart, said press plates between themselves forming pressure chambers (8). In each pressure chamber there are two filter cloths (9) forming a filter element, said filter cloths being connected to each other in one piece and hanging down from a suspension rod (58) resting on guide rails (86). During operation a suspension of solid particles in a liquid is introduced between the filter cloths (9) in the pressure chambers (8). The liquid is pressed through the filter cloths (9) under the influence of membranes (7) loaded by a pressurized medium and by blowing through a gas and is removed through drain channels (10, 12, 14). The filter cakes (40) remaining between the filter cloths (9) are discharged after bringing apart the press plates (3-6) by vibrating (98) of the filter cloths (9). In order to clean the filter cloths (9 ) from solid particles remaining thereon pipelike means (106) mounted on a laterally movable drip pan are inserted between the filter cloths (9) and spray downwardly directed spray jets (36, 48) of washing liquid on the filter cloths.

The present invention relates to a method and means for pressurefiltering.

The invention especially relates to the solution of the problem toloosen and discharge the filter cake as well as the washing and cleaningof the filter cloths such a filter.

There are previously known pressure filters, for instance shown GermanPatent Publication 3.341.636 and 3.527.735, in which the suspensionmeans of the filter cloths in both cases are suspended from the pressplates of the pressure filter by protruding, hinged brackets andsprings, while the lower ends of the filter cloths are substantiallyrigidly affixed to the press plates. The filter cloths are vibrated bymeans of a travelling vibration device, which is acting directly on thesuspension rods of the filter cloths. In these previously known devicesthe filter chambers of the pressure filter are discharged one at a time,which results in very long discharge and cleaning times. Especiallyduring short cycle times and great filter cake capacity this results inuneconomically and unreasonably long discharge times for such a pressurefilter. The fixation of the filter cloths in the lower part of the pressplates also results in severe strains and increased wear of the filtercloths.

As shown in German Patent Publication 3.527.735 there is also known apressure filter with a travelling, vertically movable cleaning device,which is cleaning the filter cloths in one filter chamber at a time.This also results in very long cycle times for the filter cloth cleaningoperation.

French Patent No. 1.335.850 describes a pressure filter comprisingweights at the lower edge of the filter cloths for the tension thereof.However, this filter does not comprise any means for the vibration ofthe filter cloths. Furthermore, also in this case the cake discharge iseffected one filter chamber at a time, which results in thedisadvantageous long cycle times mentioned above.

In order to overcome these problems of the Prior Art, a pressure filterhas been developed, which is able to discharge the filter cakes in allthe filter chambers at the same time and also is able to flush and cleanall the filter cloths at the same time. This means of course aconsiderable improvement compared to the old technique, however,especially for short cycle times and great filter cake capacity, thetime used for cake discharge and filter cloth cleaning remains aproblem.

In order to elucidate this previously known pressure filter and thedrawbacks and disadvantages thereof reference is made to "Book ofInstruction Manual for Kurita Automatic Filter Press, KUF-10", September1983, published by Sala International AB, Sala, and to the appendedFIGS. 1-3, which during various process stages discloses a section ofsuch a filter press, in which section irrelevant components areexcluded.

Such a previously known pressure filter comprises a frame 2, (not shown)a stationary end or head plate 3, a movable end or head plate (not shownin FIGS. 1-3), as well as press plates 5, 6 arranged therebetween. Atleast every second press plate 5 is provided with a membrane 7 on atleast one side thereof. Through a supply conduit F the underside of saidmembrane can be supplied with a pressurized medium, for instance ahydraulic liquid or pressurized air. Between themselves the press plates5, 6 and/or the end plates are in pairs forming pressure chambers 8. Ineach pressure chamber 8 there are arranged two filter cloths 9. Outsidethe filter cloths, the walls of the pressure chambers exhibit drainchannels 10 arranged in the plates 3-6 and the membrane 7 respectively,said channels through conduits 12 being connected to holes passingthrough the plates. Also between the press plate 5 and the membrane 7there are arranged distribution channels 16 corresponding to the drainchannels 10 for said pressurized medium. Some of the holes connect withconduits B, E for separated liquid, while other conduits C, D serve bothas outlet for separated liquid and as inlet for pressurized gas, as willbe explained in detail below.

The filter cloths 9 are sewn together at the top and fastened tosuspension bars 18. Furthermore, the filter cloths 9 exhibit feed portfixtures 20 which, when the plates 3-6 are brought together, sealinglyconnect to a feed supply conduit A. The feed port fixture exhibitspassages 22, which connect the feed supply conduit A with respectivepressure chamber 8. The suspension bar is suspended by two pulling wireropes 24 connected at the other end with wire rope drums 26. The wirerope drums are non-rotary and axially movably arranged on two hexagonalshafts 28 connected to a lifting and descending motor. At their lowerends the filter cloths pass guide members 30 and then the filter clothsare two and two rolled onto spring-loaded cloth rollers 32 similar to aroller blind roller. Furthermore, there are pipe-shaped members 34constituting supply means G for washing liquid and exhibiting nozzles 36intended for spraying washing liquid onto the obliquely opposed filtercloth 9. The guide members 30, cloth rollers 32 and the pipe-shapedmember 34 are arranged to simultaneously being brought along duringmovements with the press plates 5, 6 and the movable end plate.

The function of the press filter is as shown in FIG. 4, the press plates5, 6 and the movable end plate 4 are initially brought together with theaid of at least one hydraulic cylinder 38. Then a for moisture removalintended suspension of solid particles in a liquid, for instance a watersuspension of ore concentrate with 65% solids is introduced through thefeed supply conduit A and the passage 22 of respective feed port fixture20 in between the two filter cloths 9 of each pressure chamber 8, saidfilter cloths forming a filter element. The suspension is introducedunder high pressure, for instance 4 bars. The main portion of the liquidis already now driven through the filter cloths and the moisture isalready at this stage reduced; for ore concentrate to 86-88% solids.When the pressure chambers have been filled the suspension is removedfrom the feed supply conduit A by flushing with pressure air and cleanliquid. A pressurized medium is now introduced through a supply conduitF between the press plates 5 and the membranes 7, such that themembranes compress the filter cakes 40. In doing so, the moisturecontent is further reduced in the filter cake. During these processstages the separated liquid is removed through both the outlets B, E andthe combined inlets and outlets C, D. After that the membranes arerelieved from pressure and a pressurized gas, for instance pressure air,is introduced through the inlets C, D and blown through the filter cakesunder continued reduction of the moisture content. In this way amaximally demoisturized filter cake is produced, which for an oreconcentrate typically may contain a remaining moisture content of forinstance 6.0-6.5% water.

When the moisture removal is finished the press plates 5, 6 are broughtaway from each other by means of the hydraulic cylinders 38, such thatgaps 44 defined by distace limiting means are created therebetween. Thefilter cloths are lowered through the bottom gap by unrolling thepulling wire ropes 24 from the rope drums 26. The spring-loaded clothrollers 32 are then rolling up the lower portions of the filter clothsand are holding the filter cloths tensioned. The filter cakes formed arereleased from the filter cloth at the passage of the guide members 30.When the filter cake removal is finished the filter cloths are lifted upagain. The filter cloths are cleaned at least periodically by bringing adrip pan 46 (FIG. 5) under the filter press 1 and introduce washingliquid as obliquely upwardly directed spray jets 48 during a repeatedlowering of the filter cloths. Only one of the filter cloths 9 in eachchamber can be washed at the same time, since the spray jets 48otherwise would interfere with each other.

This previously known system for filter cloth suspension and filter cakeremoval has several drawbacks. In spite of the washing there occurobstacles and other troubles during the rolling up of the cloth on thecloth rollers because of remaining particles on the filter cloths.Furtheron, the rinsing and cleaning effect is unsatisfactory since thewashing liquid is spread on in an upward direction, and consequentlydirected in counter-current to the washing liquid leaving the filtercloths. Other drawbacks with the spring-loaded cloth rollers is a bigbuilding height of the machine, a mechanically vulnerable design andthat long time periods have to be spent for cloth change and repair.Changes are quite frequent, since holes in the filter cloths often occurduring operation. Also the arrangement of wire rope durms on hexagonalshafts is connected with disturbances, for instance derailment of thewire ropes. This design is also contributing to increased buildingheight. However, the most important drawback connected with this designis that the repeated lifting and lowering of filter cloth for filtercake removal and filter cloth cleaning considerably contribute to a longcycle time for this previously known pressure filter and consequently toa low production capacity.

The object with the present invention is, therefor, to bring about amethod and a means for pressure filtering of the kind described above,which gives a faster cycle time for the filtering operation, an improvedcleaning of the filter cloths by concurrent washing and a reduced timeconsumption for filter cloth changes and other repairs. Further, theinventive pressure filter shall have a lower building height, a moresimple construction with a smaller amount of moving parts and generallygiven an improved and more economic press filter construction.

By the fact, that according to the invention, the suspension means ofthe filter cloths are longitudinally movably supported separate from thepress plates by guide rails being possible to vibrate instead of byprotruding, hinged brackets, it is possible to discharge the filtercakes in all the filter chambers at the same time with short cycletimes. By vibrating the filter cloths with the aid of the guide rails itis possible to achieve a fast and effective filter cake dischargewithout the need of any time consuming lowering and rising movements ofthe filter cloths.

By spraying washing liquid on the filter cloths in this way for cleaningthereof, it is possible to further reduce the cycle times. By cleaningthe filter cloths in this way according to the invention it is no longernecessary to lower the filter cloths for cleaning as described above forthe most pertinant Prior Art. Compared to a travelling cleaning deviceas described in German Patent Publication No. 3.527.735 the time gainsare of course even greater.

According to an advantageous embodiment of the invention the filtercloths are cleaned by spraying washing liquid thereon through nozzlesarranged on pipelike means being insertable between the filter cloths.Spray nozzles may also be arranged on pipelike means along the sides ofthe plates and/or pipelike suspension means for the filter cloths. Inthis way a fast cleaning of the filter cloths is achieved at the sametime as washing liquid is sprayed on in concurrent with the flow ofwashing liquid leaving the filter cloths.

According to a further advantageous embodiment of the invention thefilter cloths are tensioned, and/or loaded by weights affixed to thoseparts of the filter cloths protruding underneath the press plates,preferably by rods introduced in the bottom hem of the filter cloths.

According to another advantageous embodiment of the filter cloths aretensioned with the aid of spring means, preferably helical springs orrubber bands affixed to the parts of the filter cloths protrudingunderneath the press plates.

By the use of these two alternative filter cloth tension means the needfor vulnerable and mechanically complicated spring-loaded cloth rollersof roller blind-type is eliminated.

By the use of the measures described above it has been possible toreduce the cycle time for the filter cake removal and washing of thefilter cloth about 40%.

According to a further advantageous embodiment of the invention situatedon each side of respective press plate, the two filter cloths areconnected with each other underneath said press plate, said filtercloths exhibiting tension and loading means connected to each otherand/or common tension and loading means. In this way there is no longerany need for separate guide means 30 for preventing the parts of thefilter cloths hanging underneath from hindering the filter cakedischarge.

According to further advantageous embodiments of the invention the twofilter elements forming filter cloths in each pressure chamber are madein one piece and are freely hanging over their suspension meansseparated from each other, exhibit one half each of a feed port fixturewith passages to respective pressure chamber, and exhibit positioningaiding means, such as holes provided with eyelets, co-operating withpositioning means arranged on the filter cloth suspension means. Thesearrangements together with the arrangements mentioned above at the lowerends of the filter cloths contribute to a reduced time consumption forfilter cloth exchange. It has been possible to reduce this time fromabout half an hour to only two minutes.

Further favourable features of the invention are disclosed in thefollowing description.

The invention will now be described in detail with the aid ofexplanatory examples and with reference to the attached drawing. Inorder to make the drawing more easily understandable the figures aremade substantially to schematic form, and features irrelevant to theinvention have been excluded. In the figures shows:

FIG. 1 is a partial sectional view of a previously known press filterduring filtering exhibiting a lifting and lowering means,

FIG. 2 a section corresponding to the section of FIG. 1 showing the samefilter press during a filter cake discharge sequence and also exhibitingcloth uprolling means and guide means for filter cloths,

FIG. 3 a section corresponding to FIG. 2 showing the washing of thefilter cloths,

FIG. 4 a schematic elevated view of a press filter according to theinvention in open and closed position,

FIG. 5 a cross-sectional view of the press filter of FIG. 4 in openposition, the filter cloth being removed in the sectional plane shown,

FIG. 6 a view corresponding to FIG. 5 of an alternate embodiment of apress filter according to the invention,

FIG. 7 a schematic, partial cross section through a press filteraccording to the invention showing filter cloth suspension, feed portfixtures for a particle suspension and the lower portion of the filtercloths in closed position,

FIG. 8 a sectional view corresponding to FIG. 7 in open position alsoshowing a vibrator, and

FIG. 9 a partial cross sectional view showing a guide rail for thefilter cloths suspension means with appending console.

Referring now to FIG. 4, there is shown a general side view of aninventive press filter 1 comprising a frame, a stationary end or headplate 3, a movable end or head plate 4, and intermediate press plates 5,6.

The movable press plates 5, 6 and the movable head plate are slidablymounted on guide bars 50 of the frame and are possible to bring apartand together respectively with the aid of two double action hydrauliccylinders 38. The end or head plates 3, 4 and the press plates 5, 6exhibit distance limiting means 42, shown only in FIG. 6, in the form ofroller chains, said distance limiting means being used for bringingapart the plates and limiting the distance therebetween when the pressfilter is opened. Under the press filter there is a drip pan 46 which isremovable on guide and run rolls 52 or slide rails. Under the pressfilter there is a receiving opening 54 for dried material and twocollecting launders 56 for washing liquid and particles washed away.

On the frame and the stationary end or head plate there are connectionsfor inlet conduits as well as outlet conduits A, B, C, D, E, F. Theinlet connection F is connected to connections F on themembrane-provided press plates 5 through flexible tubing, not shown indetail. The construction of the end or head plates 3, 4, the pressplates 5, 6 and the membranes 7 coincide with the previously knowntechnique as described above and as shown in FIGS. 1-3.

The arrangement and suspension of the filter cloths 9 are best shown inFIGS. 7 and 8 showing partial sections through the press plates as wellas the filter cloths and their suspension means. The press plates 5, 6including their membranes are only shown by their outside contour. Ineach pressure chamber 8 there are two substantially vertical filtercloths 9 which are forming a filter element. The cloths are made in onepiece and are suspended over a pipelike suspension rod 58. The positionon the suspension rod 58 of the two cloths is fixed by protrusions 60which are engaging holes in the filter cloths provided with eyelets 62(see FIG. 9). This fixation of the position is necessary, because thetwo filter cloths 9 are not sewn together with each other at the top.The feed port fixture 20 of the filter cloths is separated in twoseparate halves 20' and 20" respectively, which are affixed to one eachof the filter cloths in level with the feed supply conduit A of thepress plates. By this arrangement it is possible to separate the twohalves 20', 20" and consequently the filters cloths 9 from each other,when the press plates 5, 6 are brought apart. In the through flowpassages 22 of the feed port fixtures the two halves exhibit distancestrips 64 intended to prevent the feed port fixture to be compressedtogether by membrane pressure or pressure from flowing-through air. Thedistance strips may be arranged right opposite each other as shown inthe figures, or alternatively be arranged at the side of and overlappingeach other, in which case they in closed positions are abutting theopposite wall 66 of respective feed port fixture half 20', 20".

The parts of the filter cloths 9 protruding under the lower edge of thepress plates in their lower hem have introduced through-rods 68. Withthe aid of their weight they load the filter cloths and keep themtensioned. As shown in FIG. 6, the rods 68 belonging to the cloths oneach side of respective press plate 5, 6 are connected in pairs witheach other at each end by connecting means, such as rubber bands 70arranged in grooves. Because the rods are held together in pairs nospecial guide members 30 are required for keeping the filter cloths 9apart during the filter cake discharge and the filter cloth wash. Inorder to further improve the filter cloth tension and the loading of thefilter cloths 9 elastic spring means may be arranged on the rods 68. Anexample is shown in FIG. 8 in the form of a helical spring 72 affixed toa console 74 protruding downwards from the associated press plate. Suchelastic means prevent the rods and the lower parts of the cloths fromswinging sidewards.

The parts of the filter cloths 9 protruding under the press plates 4, 5and their rods 68 may also be free from each other. The thickness of thesuspension rods 58 will bring them apart when the press plates areseparated. Therefor, relatively thick suspension rods are preferred.During vibration, as described below, the rods will jump and jerk, thusstetching and cracking the filter cloth and removing the filter caketherefrom. The free lower ends also provide for a very fast filter clothexchange, especially if all filter cloths are exchanged at the same timeas described below.

The suspension rods 58 are pipe-shaped and are provided with downwardsdirected spray nozzles 36 for washing liquid introduced through a supplyconduit G. At one of the ends they have a connection 76 which via aflexible hose 78 connects to a distribution pipe 80 (see FIG. 6). Thepipe 80 is supported by posts 82, which are anchored to the the near-byfloor or the like 84.

The suspension rods 58 are supported movably in the longitudinaldirection of the filter press on guide rails 86. In order to reduce thefriction they may be provided with ball bearings 88 or other bearings.In order to position the suspension rods 58 with their protrusions 60directed upwards they exhibit rectangular guide or distance plates 90which are abutting guide lists 92. The plates 90 are also defining thepositioning of the supsension rods 58, when the press plates are intheir closed position. The various suspension rods 58 are linkedtogether by distance means 94 which are defining the distance betweenthe suspension rods, when the press plates are situated in open orbrought apart position. In the embodiment shown the distance means 94comprise roller chains, of the bicycle chain type, but they may alsocomprise other flexible and/or articulated means.

The guide rails 86 are supported at both ends by vibration dampers 100and consoles 102, which are connected to the frame in appropriate way.The two guide rails 86 are provided with at least one vibrator 98,preferably one at each end. According to a first embodiment, each guiderail may be provided with at least one such vibrator and the guide railsare vibrated independently. According to a second embodiment, the twoguide rails 86 are connected at the ends by two yokes shown with dashedlines 96 in FIGS. 5 and 8, thus forming a frame. One at least one of theyokes there is provided a vibrator 98 for vibrating the guide rails inunison.

The suspension rod 58 situated closest to the movable end or head plateis through the distance or connection means 94 connected to the movableplate 4, for instance with posts 104 protruding from said plate andshown only in FIG. 4. Said posts 104 comprise abutment surfaces forabutting the guide and distance plates 90 of the nearest suspension rod58. Consequently, with the aid of the post 104 the suspension rods 58and, consequently, the filter cloths 9 can be brought to follow thepress plates 5, 6 in their movements when the press plates are broughtapart and together.

For the cleaning of the filter cloths there are provided pipe-like means106 and, preferably, downwardly directed spray nozzles 36 connected todistribution pipes 108 which in turn are connected to a supply conduit Gfor washing liquid. The distribution pipes 108 and the pipelike means106 are fastened to posts 110 which are protruding from the drip pan 46and are following the drip pan in its movements. In this way it ispossible to at the same time as the drip pan is moved in below the pressfilter introduce the pipelike means 106 with its spray nozzles betweenthe filter cloths 9 in each pressure chamber 8 for spray cleaning of thefilter cloths. It is possible to arrange an arbitrary amount of pipelikemeans 106 at different levels in order to achieve a desired or necessaryclean-washing effect. It is possible to provide downwardly directedspray jets 48 of washing liquid for concurrent washing, but also sprayjets directed sideways or upwardly if one wishes to do this.Alternatively, the pipelike means 106 may be affixed to separate guideand run rolls or sliding rails and be moved independent of the drip pan46.

Referring now to FIG. 6 pipelike means 112 with substantially sidewaysdirected spray nozzles 36 can be also arranged along the sides of theplates. The pipelike means are connected to a supply conduit G forwashing liquid and can distribute such washing liquid on to the filtercloths 9 from the sides, when the press plates are in their open orbrought apart position. Of course, it is possible to combine one orseveral of the above described ways of washing the filter cloths 9 withwashing liquid; viz. by spray nozzles 36 arranged on the pipelikesuspension rods 58 for the filter cloths and or arranged on pipelikemeans 106 insertable between the filter cloths and/or arranged onpipelike means 112 arranged along the sides of the plates.

The function and the working mode of the inventive filter press are asfollows: Initially, the press plates 5,6 and the end or head plates 3,4are brought together, then a suspension of fine particles in a liquid isintroduced and is demoisturized as described above for the previouslyknown technique with reference to FIGS. 1-3. When the demoisturizing isfinished the plates are brought apart by the hydraulic cylinders 38.Simultaneously, with the aid of the distance limiting means 94 thesuspension rods 58 are brought to take central positions over theintermediate gaps 44 created between the plates of the filter press. Thefilter cloths 9 are brought apart from each other by the tension andloading effect of the weight of the rods 68 and/or separate springmeans, such as helical springs 72 or rubber bands. After that, the guiderails 86 are vibrated during a short time period in vertical directionby the vibrators 98. The guide rails in their turn vibrate suspensionrods 98 with the filter cloths 9, thus the filter cakes 40 swiftly andcompletely are disengaged from the filter cloths 9 and fall down throughthe receiving opening 54. Next, the drip pan 46 is pushed over thereceiving opening 54 by an hydraulic cylinder 114, at the same time aspossibly provided pipelike means 106 are inserted between the filtercloths 9 in respective pressure chamber 8. After that, the filter cloths9 are washed clean from solid particles by spraying with liquid from thespray nozzles 36. At the end of the washing, the filter cloths aresubjected to another short vibration by the vibrators. In this way, thefilter cloths are relieved from most of the washing liquid, and this isprevented from dripping down into the receiving opening 54. After thewashing, the pipelike means 106, if any, are removed and the plates ofthe press filter are brought together again. A new filtering cycle canbegin.

According to a especially favourable embodiment of the invention, theguide rails 86 are connected at their ends by yokes 96 to form a frame,said frame being disconnectable from its flexible and resilientsuspension means 100. This makes it possible to remove and exchange theentire filter cloth package comprising said frame, with all thesuspension rods 58 and their filter cloths 9. All that is needed is toopen the press filter and disconnect the power supply means for thevibrating means and the flexible connection conduits 78 for washingliquid to the pipelike suspension means 58. Then the rods 68 at thelower end of the filter cloth 9 are disconnected from each other andfrom the spring means 72 if such are provided. In this case it isespecially favourable if the rods 68 are free from each other asdescribed above. After the disconnection of the guide rails from theflexible vibration dampers 100 the entire package can be lifted out. Inorder to facilitate the lifting out and replacement of the frame withthe filter cloths vertical guide means (not shown) may be inserted inholes in the end or head plates 3, 4 and pass through suitable guiderings arranged in the frame formed by the guide rails and the yokes. Inthis way the filter cloths 9 can be exactly guided in between therespective gaps 44 between the press plates.

In this way it is possible to replace the entire filter package for anexchange unit. This is especially favourable when there is a need for aperiodical cleaning of all filter cloths. This is the case in somechemical and industrial processes where a chemical precipitation mayoccur in the filter cloths. The entire package can then be placed in abath and treated with suitable solutions for dissolving theprecipitates. In the meantime the press filter is working at fullcapacity with the exchange unit.

The invention is not limited to the embodiments described above andshown in the figure, but can be modified in many various ways within thelimits of the inventive concept and the following patent claims.

What we claim is:
 1. A method for filtering on a press filter (1), whichcomprises a number of press plates (3, 4, 5, 6), which can be pressedagainst each other and are provided with drain conduits (10, 12), saidpress plates two and two between themselves forming at least onepressure chamber (8), two substantially vertical filter cloths havingsuspension means (18) being suspended in each pressure chamber (8), andmeans to introduce a suspension of solid particles in liquid into eachpressure chamber (8) to cause the liquid to pass through the filtercloths (9) and to be evacuated through said drain conduits, the solidparticles remaining in each pressure chamber, said particles forming afilter cake (40) between the two filter cloths, comprising the stepsof:separating the press plates, and discharging the filter cake fromsaid pressure chamber (8), the filter cloths (9) being vibrated duringsaid discharge, moving said filter cloths (9) with their suspensionmeans (58) in a horizontal direction during the pressing against eachother and the bringing apart of said press plates, and during the filtercake (40) discharge, vibrating all of the filter cloths (9) and theirsuspension means (58) simultaneously.
 2. A method according to claim 1,including the steps after the filter cake is discharged of spraying awashing liquid over the filter cloths through nozzles and vibrating thefilter cloths during the spraying with washing liquid.
 3. In anapparatus for pressure filtering in a press filter (1) for the removalof liquid from a suspension of solid particles in said liquid, saidpress filter comprising a number of press plates (3, 4, 5, 6), which canbe pressed against each other and are provided with drain channels, saidpress plates two and two between themselves forming at least onepressure chamber (8), two substantially vertical filter cloths (9),suspension means (18) for suspending two filter cloths in each of saidpressure chambers (8), a feed supply conduit to introduce saidsuspension under pressure between the filter cloths (9) in said pressurechamber (8), said liquid being removed under the influence of the inletpressure, through the filter cloths (9), and through the drain channels(10, 12) of the press plates, while the solid particles in the form offilter cakes (40) remain between the filter cloths (9), and means toseparate the press plates (3, 4, 5, 6) to discharge the filter cakesfrom the pressure chambers (8), the improvement wherein said pressfilter further includes:guide rails supporting said suspension means(58) of the filter cloths (9) at both ends for horizontal movement inthe longitudinal direction of the press filter, said guide rails beingresiliently suspended, and vibration means (98) for simultaneousvibrating of all suspension means (58) with appending filter cloths (9),and distance means (94) affixed to the ends of said suspension means,said distance means connecting the suspension means with each other andwith the press plates.
 4. Apparatus as claimed in the claim 3, includingguide plates on said suspension means and guide surfaces engaging saidguide plates, said suspension means (58) being prevented from turningaround their longitudinal axes by said guide plates (90) and said guidesurfaces (92), when the press plates (3, 4, 5, 6) are brought together,the positions of the suspension means (58) being defined by the guideplates (90).
 5. Apparatus as claimed in the claim 3, wherein saidvibration means vibrate said guide rails (86) in substantially verticaldirection.
 6. Apparatus as claimed in claim 3, wherein the bottom partsof said filter cloths extend downwardly beyond the lower end of saidpressure chambers and include means for tensioning of the filter cloths(9) affixed to said bottom parts of the filter cloths.
 7. Apparatus asclaimed in claim 3, wherein the two filter cloths (9) in each pressurechamber (8) are hanging from opposite edges of their suspension means(58) separated from each other to accommodate therebetween a feed portfixture (20) with passages (22) to the associated pressure chamber (8).8. Apparatus as claimed in claim 3, including movable pipe means (106)having nozzles (36) and a supply conduit (G) for washing liquid, saidmeans (106) having mounted thereunder a movable drip tray (46) forfollowing it in its movements; said means (106), when the press platesare brought apart, being insertable in said pressure chambers (8)between the two filter cloths (9) in order to clean said filter cloths.9. Apparatus as claimed in the claim 3, wherein said suspension means ofthe filter cloths are pipe means (58) having downwardly directed nozzles(36) and connections to a supply conduit (80) for washing liquid, saidapparatus including second pipe means (112) having connections to asupply conduit (G) for washing liquid and nozzles (36) along the sidesof the press plates.
 10. Apparatus as claimed in the claim 3, includingyokes connecting said guide rails (86) at their ends to form a frame,said frame being disconnectable from its resilient suspension means(100) and said vibrating means (98), said frame being removable forrepair or cleaning as a unit together with all the suspension means (58)and filter cloths (9) for repair or cleaning of the filter cloths (9) orexchange for similar replacement unit.